Importance of potency in typing by colicine production

McGeachie, J.; McCormick, William H.

doi:10.1136/jcp.20.6.887

Cited by 10 publications

(7 citation statements)

References 9 publications

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“…Unlike the supernatant, it was inactive against strains 267 and 26. This difference, as in the case of colicins (McGeachie & McCormick, 1967), could be explained by the difference in bacteriocin concentration used for the assays (200 AU ml-1 for the supernatant and 10 A U ml-l for purified bacteriocin).…”

Section: Isolation Of Bacteriocin From P Solanacearm S Lmentioning

confidence: 99%

Isolation and Characterization of a Bacteriocin Produced by Pseudomonas solanacearum

Cuppels¹,

Hanson²,

Kelman³

1978

Journal of General Microbiology

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Strain s l , an avirulent non-slime-producing variant of Pseudomonas solanacearum ~6 0 , had greater bacteriocinogenic activity than did strain ~6 0 both in liquid and on solid medium. The bacteriocin synthesized by strain ~l inhibited the growth of 43 of 51 P . solanacearum strains tested. It had no effect on strain ~l , strain ~6 0 , or selected strains from 10 other bacterial species. Although the optimal growth temperature for strain ~l was 32 "C, the temperature most favourable for bacteriocin production was 30 "C. Bacteriocin titre could be increased by short exposure to ultraviolet light but not by chemical inducing agents.The bacteriocin produced by strain ~l was purified from the culture supernatant by ammonium sulphate precipitation, anion exchange chromatography, membrane ultrafiltration and preparative electrophoresis. Purified bacteriocin, being non-sedimentable, thermolabile and sensitive to proteolytic enzymes, resembled the S-type bacteriocins produced by P. aeruginosa. As determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, the purified bacteriocin had a molecular weight of approximately 65 000. It was insensitive to chloroform, nucleases and phospholipase. Although the bacteriocin present in culture supernatant was stable for 3 months at 4 "C, the activity of purified bacteriocin declined rapidly under a variety of storage conditions. Maximum pH stability was between 6 and 8.

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Section: Isolation Of Bacteriocin From P Solanacearm S Lmentioning

confidence: 99%

Isolation and Characterization of a Bacteriocin Produced by Pseudomonas solanacearum

Cuppels¹,

Hanson²,

Kelman³

1978

Journal of General Microbiology

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“…A source of error which may occur in the stroke plate method of bacteriocine typing has been pointed out by McGeachie and McCormick (1967). These authors advocate extraction of bacteriocine, lest weak bacteriocine production should be missed.…”

Section: Discussionmentioning

confidence: 99%

An evaluation of three methods of typing organisms of the genus Proteus

1972

J Clin Pathol

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SYNOPSIS An assessment of three simple methods of typing Proteus strains is described. The methods chosen were biochemical typing, bacteriocine typing, and typing by means of the Dienes phenomenon. Dienes typing was deemed to be superior to biochemical typing and bacteriocine typing.A brief discussion on the relationship between the Dienes phenomenon and bacteriocine production is appended.Proteus infections in hospital practice may present a therapeutic problem, since Proteus species readily develop resistance to antibiotics (Carpenter, 1964).The extent to which Proteus cross-infection occurs is hard to assess, and in evaluating this problem difficulty arises because the infection may be exogenous or endogenous; since it is impossible to distinguish between these two routes of infection this problem must remain unsolved until a suitably simple and accurate tyDing system is made available.Several methods have been used: serology (Belyavin, Miles, and Miles, 1951;Krikler, 1953; Nestoresco, Popovici, Racovitai, Dimitriu, Floresco, Mermezan, Filipesco, Thomas, and Dragan, 1963), biochemistry (Kippax, 1957;Huang, 1966), Dienes typing (Krikler, 1953;Story, 1954;De Louvois, 1969;Skirrow, 1969). Bacteriocine typing (Cradock-Watson, 1965) and bacteriophage typing in conjunction with biochemistry (France and Markham, 1966) have all been employed.We wished to select a method suitable for a diagnostic laboratory rather than a reference laboratory, and accordingly chose the simplest of the available methods for study. For this reason, serology and bacteriophage typing were excluded as being too cumbersome for such a purpose. The remaining methods-biochemistry Dienes typing, and bacteriophage typing-were selected for evaluation. It was thought that these methcds were particularly suitable, as they required only simpleequipment and were not time-consuming. 'Present address:

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“…This lack of reproducibility could not be due to an instability of the indicator strains, because serial isolates from patients typed simultaneously showed a remarkable constancy of type. It might be due to a variation in potency; McGeachie and McCormick (1967) observed such a variation when strains were re-tested by the same methods of preparation of medium and colicine extraction.…”

Section: Discussionmentioning

confidence: 99%

Colicine Production as an Epidemiological Marker of Escherichia Coli

Hettiaratchy

Cooke

Shooter

1973

Journal of Medical Microbiology

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THE epidemiology of Escherichia coli is poorly understood, and although serological characterisation of strains affords an excellent method of typing E. coli, it is time-consuming and can be performed only in specialised laboratories. Another method would be of value. Colicine typing as a method of differentiating strains has been used (Linton, 1960;McGeachie, 1965 ;Mustafa and Dunbar, 1970), but not so extensively as serotyping and its usefulness has not been defined.Colicine typing is simple to perform and has been found valuable in epidemiological studies on shigellae (Abbott and Shannon, 1958 ;Gillies, 1964;Hart, 1965), particularly on strains of Shigella sonnei because they are serologically and often biochemically homogeneous (Hart).This paper records our experience of colicine typing of E. coli and of the validity of the method as an epidemiological tool. Serological and colicine typing were used in this investigation to determine whether the combination of the two methods would provide a finer subdivision of strains, to show the frequency of colicine production and sensitivity among serologically defined strains, and to show any correlation between colicine types and antigenic structure of the organisms. This is particularly interesting because several workers attempting to purify colicines have observed a close association between colicines and the 0 antigen of the organism (Goebel and Barry, 1958;Hutton and Goebel, 1961;Barry, Everhart and Graham, 1963).An epidemiological application of the typing method is also reported. MATERIALS AND METHODS Specimensof faeces were collected from patients in a female, open medical ward as soon as possible after admission and thereafter at weekly intervals for 1 yr. The patients were those usually seen in a general medical ward and particularly included diabetics.

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Importance of potency in typing by colicine production

Cited by 10 publications

References 9 publications

Isolation and Characterization of a Bacteriocin Produced by Pseudomonas solanacearum

Isolation and Characterization of a Bacteriocin Produced by Pseudomonas solanacearum

An evaluation of three methods of typing organisms of the genus Proteus

Colicine Production as an Epidemiological Marker of Escherichia Coli

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